Base64 Decoder
Decode Base64 strings and JWT payloads back into readable UTF-8 text with zero server transmission. Completely private and safe for tokens.
100% Client-Side · In-Memory Only
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How to Use Base64 Encode / Decode
- Select whether to Encode to Base64 or Decode from Base64.
- Check "URL-safe alphabet" if you need web-safe base64 strings (- and _ with no padding).
- Paste your string and copy the converted output with one click.
Features & Guarantees
- Full UTF-8 support including international characters and emojis.
- URL-safe alphabet mode compatible with JWTs, URLs, and filenames.
- Calculates input bytes vs output characters in real time.
Frequently Asked Questions
Does this handle multi-byte UTF-8 emojis?
Yes. The converter implements full URI encoding prior to binary conversion, ensuring emojis and non-Latin characters decode without corruption.